Generally, vacuum circuit breakers are circuit and appliance protecting apparatuses in which an arc generated when switching a normal load or blocking a fault current is extinguished in a vacuum interrupter in order to rapidly separate a circuit. Such a vacuum interrupter is made of an electrically insulating material such as ceramic as a key component of a vacuum circuit breaker. In addition, a movable contact and a fixed contact are provided inside an insulated housing with a vacuum state therein, so that an arc generated when switching is performed is rapidly extinguished. Thus, vacuum circuit breakers are used as contacting devices for switching a power system.
FIG. 1 is a configuration diagram of a general conventional vacuum interrupter. A conventional vacuum interrupter 10 includes a fixed electrode 12 and a movable electrode 14, and a housing 11 that is vacuum sealed so that inside thereof is maintained in a vacuum state, the fixed electrode 12 and the movable electrode 14 being provided in the housing 11. The fixed electrode 12 is fixed on a fixed member 18. The fixed electrode 12 and the movable electrode 14 are attached with a fixed contact 13 and a movable contact 15, respectively. The fixed electrode 12, the fixed contact 13, the movable electrode 14, and the movable contact 15 are installed on the same straight line. In addition, a known bellows 16 is installed inside the housing 11 on the side of the movable electrode 14.
In addition, a movement unit 17 is installed outside of the housing 11 so that the movable electrode 14 straightly moves. The movement unit 17 straightly moves the movable electrode 14 so that the movable contact contacts with and separates from the fixed contact 13 of the fixed electrode 12, thus an electric short circuit is formed and released within the vacuum interrupter 10.
However, in the conventional vacuum interrupter 10, speed in forming and releasing a short circuit is limited since the movable electrode 14 only straightly moves to contact with and separate from the fixed electrode 12 that is fixed in one side. Particularly, in a high voltage direct current transmission (HVDC) system, such speed is important since forming and releasing a short circuit in a vacuum interrupter has to be performed at a high speed. However, in a conventional method, there is a limit to increasing speed since the movable electrode 14 only moves to form and release the short circuit.
In addition, since the movable electrode 14 straightly moves and contacts the fixed contact 13 to form a short circuit in the vacuum interrupter 10, mechanical impact occurs at the fixed contact 13. Such an impact may cause misalignment between the fixed contact 13 and the movable contact 15, or may become a cause of various deformations, or cracks. In addition, the impact may also adversely affect vacuum tightness of inside the housing 11.
In order to solve the above problems, a configuration that absorbs the mechanical impact within the conventional vacuum interrupter is provided. The impact applied to the fixed electrode 12 is absorbed by installing an impact absorbing means outside the housing 11 on the side of the fixed electrode 12.
However, in such a conventional method, since the movable contact 15 moves fast and contacts the fixed contact 13, it cannot fundamentally solve the problem caused by the mechanical impact applied to the fixed electrode 12 and the fixed contact 13.